Technical Field
The present disclosure relates to a cooling device for a transformer, and more particularly, to a cooling device for a transformer that reduces heat generation from a transformer disposed within a battery charger of an eco-friendly vehicle.
Background Art
In general, an eco-friendly vehicle, (e.g., Plug-in Hybrid Electric Vehicle (PHEV) or Electric Vehicle (EV)) includes an on board charger (OBC) configured to charge a high-voltage battery that is a power supply of a driving motor. The OBC receives alternating current (AC) power from an external power supply to charge the battery. An OBC circuit for an eco-friendly vehicle is generally configured in the form of a combination of a power factor corrector (PFC) and a full bridge converter, and a transformer is disposed between the PFC and the full bridge converter to be isolated from high-voltage battery.
However, heat generation from the transformer within the OBC circuit may be substantial, and to reduce heat generation from the transformer, various methods such as using a molding structure have been used. Such methods may have several problems that include increasing production costs and exhibiting difficulties in manufacturing.
An exemplary sectional view of a transformer for OBC according to a related art is shown in FIG. 5. Referring to FIG. 5, the transformer for OBC according to a related art requires leakage inductance (generally, 10 uH or more) to ensure zero voltage switching (ZVS) of a phase shift full bridge (PSFB) circuit. Further, to generate such leakage inductance, a primary winding 1 is separated from a secondary winding 2. To support the primary winding 1 and secondary winding 2 and maintain the gap between the primary and secondary windings 1 and 2, a bobbin 3 is inserted between the primary and second windings 1 and 2, and the bottom of a core 5 contacts a heat sink 4 to dissipate heat.
Within the transformer according to the related art, a substantial amount of heat is generated from the primary and second windings 1 and 2, and due to the generated heat, the temperature of the transformer may increase. However, since the bottom of the core 5, around which the primary and secondary windings 1 and 2 are wound, is cooled, temperature specifications may be difficult to meet.
Accordingly, to reduce heat generation from a transformer, a method of molding a transformer, a method of installing a heat-dissipating panel on an outer side of a core, etc. have been used. However, since the method of molding the transformer additionally requires a plastic or an aluminum case and molding liquid (e.g., silicon having high thermal conductivity), production costs may increase substantially, and the volume of the transformer may increase. Meanwhile, the installation of the heat-dissipating panel may have a low (e.g., minimal) effect on temperature reduction of the inside of the core and windings since the panel reduces the temperature of an outer side of the core.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.